In this case, should the claim be to AB or LH? AB did the right thing, but LH had the delay... so do passenger claim from AB and they in turn claim from LH?

quote:"If you are put on a replacement flight with a different airline you can still claim compensation if your flight arrives three hours or more after the original scheduled time. In this instance however you would claim against the original airline that you booked with and not the carrier operating your replacement flight."
unquote

AB has been unnervingly unreliable over the past months, but they have paid several claims for compensation under the EC rule without shenanigans.
It just took them a while to respond to the complaint (several weeks), but its the result which matters for me.

Contacted a few weeks back regarding a cancelled flight on AB8730 TXL-LIN, which is an AB flight operated by AZ aircraft and crew, but has no AZ flight number. I hoped that this wouldn't be to much of an issue, but just got a response saying that they are not the operating carrier and that it should be routed to AZ.

I contacted AZ with the same information -- but this seems like a sticky situation and can imagine AZ's response being along the lines of "it was an AB flight with AB flight number." Any other experiences with such kinds of wet lease flight claims?

If both AB and AZ claim that they did not intend on operating this flight with their AOC, I would write to the LBA and complain that AB/AZ intented to fly without an AOC (which is a gross violation of the law and could lead to severe punishments).